Druids sacrificed humans by stuffing them into giant wicker men specifically to ensure a good harvest of vegetables

A closer look

Vegetables are important for a balanced diet, but setting a massive cage full of screaming humans on fire to get a better cabbage yield feels like a severe overreaction. According to Julius Caesar's accounts, Celtic druids practiced a deeply unsettling form of agricultural mysticism. They would weave colossal effigies out of wood and straw, pack them tight with living thieves and prisoners of war, and torch the whole thing to appease the gods of crop fertility.